Activity level Yellow or (III): changes in the behavior of volcanic activity.

Regarding the monitoring of the activity of the Nevado del Ruiz volcano, the SERVICIO Geologico COLOMBIANO reports:

During last week, the seismic activity of the volcano Nevado del Ruiz presented mostly events related to fracturing of the rock inside the volcano. Earthquakes are located primarily in the distal seismogenic sources from the North, West, South North and to a lesser extent in the proximal part of the West, North and East compared to the crater Arenas and in the crater itself. The depths of the earthquakes were between 1.0 and 9.4 kilometers. The largest seismic event of the week was 2.5 ML (local Magnitude) recorded on June 3 at 0:49 (local time), located 2.4 km northeast of the Arenas crater at a depth of 3, 52 km.

Seismic activity associated with fluid dynamics in volcanic conduits, characterized by the appearance of long period earthquakes (LP) and very long period (VLP), as well as episodes of continuous volcanic tremor, low level energy, were also recorded, with pulses of tremor with varying energy levels. Some of these signals are associated with the gas and ash emissions. These events were mainly located in the southeast sector of the volcano and near the Arenas crater. The registration of new seismic signals of this type with high levels of energy and emissions of ash in the atmosphere are not excluded, which can be dispersed by the wind conditions prevailing in the region.

The volcanic deformation measured from electronic inclinometers, global navigation satellite systems (GNSS) and satellite images to track changes in the tilt, the position and shape of the volcano, respectively, continued to record Changes.

The volcano continues to emit into the atmosphere large amounts of steam and water gas, including sulfur dioxide (SO2), which is distinguished as it was estimated by the permanent stations SCANDOAS installed in the region of the volcano and satellite imagery.
In the monitoring of satellite images provided by the portal Mirova it was identified a level of thermal anomaly of low energy near the Arenas crater, June 5, this during the week. The persistence of these anomalies confirms the instability of the Nevado del Ruiz volcano and confirmed that the volcanic process continues to evolve.
The column of gas, steam and ash reached a height of 1800 m, measured from the top of the volcano, on May 31 The direction of the dispersion of the column was in line with the prevailing wind in the area, which during the week showed a predominant direction towards the southwest of the volcano.